Thin or light

Its Swift 5, available in December for $999 and up, weighs 2.1 pounds — light enough to feel like an old-school laptop without its removable battery, and lighter thanalmost every laptop with a fixed keyboard. Despite that, the Swift 5 offers one USB-C port, two standard USB ports, a USB-C port that can charge the laptop, an HDMI output to connect a TV and a headphone jack. Apple’s (AAPL) lighter Macbook 12-inch, meanwhile, offers just a USB-C port and headphone jack.

Acer estimates its battery life at “only” eight hours, which has become subpar over the last few years.

Acer’s Swift 7 is incredibly thin, but has just two USB C ports and a headphone hack.

Recharge tomorrow?

Lenovo’s thicker, heavier Yoga 920 hybrid laptop offered a different way to cut down on your daily computing payload: A 15.5-hour battery life.

(Dell’sjust-updated XPS 13 laptop, starting at $800 and going on sale Sept. 12, touts the same 22 hours of battery life as the current model but can’t be folded into a tablet.)

The $1,330 Yoga 920, which features a 13.9-inch screen and weighs 3 pounds, offers both USB and USB-C ports, so you won’t have to fish out a dongle to plug in older hardware. It also recharges viaUSB-C, which means you can use its charger to revive many new Android phones orreplace it with a smaller, lighter third-party charger if you want.

The Lenovo Yoga Y920 sees its battery cut by a third when you choose a higher resolution display.

If only the same were true of the other refreshed models Lenovo had on display: The cheaper Yoga 720 hybrid laptop and the Miix 520 tablet both have proprietary power ports, even though they include USB-C ports to connect things besides their own chargers.

Dear PC vendors: Unless you can design a power connector that safely falls free if tugged hard — like Apple’s now-abandoned MagSafe or the one on the Microsoft (MSFT)Surface Pro — please accept the limits of your creativity and stick to USB-C.

Screen sickness

The Yoga 920 and the XPS 13, however, offer optional screens that cost battery life. On the 920, your step-up from the standard 1080p panel to an Ultra High Definition screen (3840 x 2160 pixels) slashes battery life by about a third, to 10.8 hours.

The XPS 13, meanwhile, offers a “Quad HD+” screen, with 3200 x 1800 pixels, that cuts your time away from an outlet from 22 hours to 13.

The HP (HPQ)Spectre x360 demands the same tradeoff: Going from 1080p to UHD whacks battery life by almost half, to 9.5 hours.

The Dell XPS 13 is one of the best laptops on the market, but its QuadHD+ display cuts down on its battery life.

And you won’t see those additional pixels from a typical viewing distance of 18 or so inches away, while 1080p will look great if not quite“Retina Display”-worthy from that range. To ensure that discrete pixels vanish from sight, a smaller increase in resolution suffices.

Apple’s 12-inch MacBook and 13-inch MacBook Pro include 2304 x 1440 screens, and my colleague David Pogue had no complaints about abouteitherscreen. The 2736 x 1824 pixels on the Surface Pro’s 12.3-inch screen? Also fantastic, if overkill (to judge from Windows being set to scale up text by 200% to avoid squint-inducing type).

(Without getting intothe algebra involved, the simplest sign of resolution overkill is the pixels-per-inch count. Those Apple models and the 15-inch MacBook Pro come in at around 220 PPI, while the Surface Pro has 267 PPI, the QHD+ XPS 13 offers 276 and the UHD Lenovo 920 hits 317 PPI.)

UHD is pointless on a 13- or 14-inch screen outside particular cases like professional image editing or gaming. Otherwise, you’d best break out a magnifying glass or be born with exceptional eyeballs to discern any benefit from it.

UHD is, however, a recognizable term thanks toits steady takeover of the TV business — even though its extra pixelsalso go unseen on many smaller sets. And, thanks to the cratering costs of displays, UHD can look cheap next to the other step-up options on the menu. So you should expect even more laptops luring buyers with this dubious upgrade at the massive Consumer Electronics Show in Las Vegas this January.